Thermoforming machine

A machine for continuously thermoforming a sheet of heat-softened thermoplastic material wherein two opposed and spaced successions of continuously circulatable tooling steps converge at an entry throat for said sheet to move said sheet from the throat through a dwell section in which the tooling steps move in opposed parallel relationship to a product removal section in which the tooling steps diverge and the formed product is removed from the machine, the said tooling steps being of sufficient widths to carry two or more rows of tools extending across the direction of sheet movement and said tooling steps while in contact with the sheet in the throat being operatively associated with means acting simultaneously to constrain the tooling steps (i) to remain in parallel alignment of the direction of sheet movement through the dwell section, (ii) to apply thrust in opposed directions normal to said direction of sheet movement, and (iii) to maintain opposed tooling steps in alignment relative to each other in the direction of sheet movement, characterised in that driving mechanisms incorporating a drive sprocket and controlling the movement of each opposed succession of tooling steps are interrelated so as to maintain said tooling steps in precise synchronism with each other irrespective of any minor variation in speed arising from cosine error in the drive sprocket.